Online advertising refers to the use of an online network such as the Internet to deliver promotional marketing messages to consumers. Online advertising may take on any of a variety of forms such as, for example, e-mail marketing, search engine marketing, social media marketing, various forms of display advertising (e.g., web banner advertising), mobile advertising, and so forth.
Malware (a shortened form for “malicious software”) may include any software that disrupts the operation of a computing device, gathers sensitive information, or gains access to private computing systems. Malware may take on any suitable form including, for example, executable code, scripts, active content, or other software. Malware includes, for example, computer viruses, ransomware, worms, Trojan horses, rootkits, keyloggers, dialers, spyware, adware, malicious browser helper objects (BHOs), rogue security software, or other malicious software.
Malvertising (a shortened form for “malicious advertising”) refers to the use of online advertising to spread malware. Malvertising may take on any of a variety of forms including, for example, pop-up advertisements for deceptive downloads (e.g., a fake anti-virus program that installs malicious software), drive-by downloads, web widgets that redirect to malicious sites, hidden iframes, malicious banner advertisements, and so forth. Malvertising may be particularly difficult to combat because infections delivered through malvertising may not require user action (e.g., a user click) to compromise a system and may not exploit identifiable vulnerabilities on a website or a server hosting the site.